Haploclonus Regan & Trewavas, 1930

Villarins, Bárbara T, Fischer, Luciano G, Prokofiev, Artem M & Mincarone, Michael M, 2023, Four new species of dragonfish genus Eustomias (Stomiiformes: Stomiidae: Melanostomiinae) from the western tropical Atlantic, with remarks on Eustomias minimus Clarke, 1999, Zoological Journal of the Linnean Society 202 (1), pp. 1-17 : 3

Subgenus Haploclonus Regan & Trewavas, 1930

Type species: Eustomias enbarbatus Welsh, 1923 .

Diagnosis: The species in the subgenus Haploclonus have: three free pectoral-fin rays; seven pelvic-fin rays; slender barbel stem with little or no external pigment; no ventral body groove; lower numbers of serial photophores IC (65–68, except Eustomias treoavasae Norman, 1930 with 65–72) and OC (56–61, except E. treoavasae with 60–65), and lower vertebral count (56–59, except E. treoavasae with 59–63) in comparison to the other three-pectoral-rayed subgenus, Nominostomias (IC 69–78; OC 63–72; and vertebrae 65–69); presence, in most species, of a row of black spots associated with photophores along part or all of the stem preceding the proximal bulb; five or six pairs of dorsal spots anterior to the dorsal-fin origin; 6–10 widely spaced teeth in both premaxilla and mandible; mobile teeth more numerous than fixed teeth ( Gibbs and Craddock 1973, Gibbs et al. 1983, Gibbs 1986, Prokofiev 2018; present study).